Valved nasal cannula

ABSTRACT

A valved nasal cannula ( 10 ) insertable in a nose of an intended user ( 14 ) and usable to selectively restrict a flow of air flowing through the valved nasal cannula ( 10 ), the nose having a nostril ( 12 ) defining a nostril inlet ( 15 ) and a nostril vestibule ( 16 ) extending inwardly into the nose from the nostril inlet  15 ), the valved nasal cannula ( 10 ) comprising: —a cannula body ( 18 ), the cannula body ( 18 ) defining a cannula passageway ( 20 ) extending therethrough, the cannula passageway ( 20 ) defining a passageway longitudinal axis ( 22 ), the cannula body ( 18 ) also defining a cannula proximal end ( 28 ) and a substantially longitudinally opposed cannula distal end ( 30 ), the cannula body ( 18 ) being, at least in part, insertable in the nostril with the cannula proximal end ( 28 ) positioned inside the nostril vestibule ( 16 ) substantially spaced apart from the nostril inlet ( 15 ) and the cannula distal end ( 30 ) positioned substantially adjacent the nostril inlet; —a valve operatively coupled to the cannula body ( 18 ) for selectively restricting the flow of air through the cannula passageway ( 20 ); and —a protective grid ( 54 ), the protective grid ( 54 ) extending from the cannula body ( 18 ) across the cannula passageway ( 20 ), the protective grid ( 54 ) being located closer to the cannula proximal end ( 28 ) than the valve.

FIELD OF THE INVENTION

The present invention relates to the general field of devices andmethods for breathing problems such as snoring and sleep apnea and isparticularly concerned with a valved nasal cannula.

BACKGROUND OF THE INVENTION

The prevalence of breathing disorders during sleep, including snoringand sleep apnea, is relatively high. Such disorders are associated withsignificant morbidity.

The harsh and rough sound known as snoring is typically caused when aperson breathes through his or her mouth during sleep in such a mannerso as to cause the soft palate and/or uvula to vibrate, but may alsooccur when the person breathes through his or her nose. In addition tothe irritating snoring sound which may cause potential marital stress,it has been suggested that mouth breathing is unhealthy. Indeed, itcontributes to the development of gum diseases such as pyorrhoea andalso to an unpleasant dry mouth syndrome.

Sleep apnea is a potentially lethal condition characterized by multiplemixed or obstructed apneas during sleep. Symptoms of sleep apnea includerepetitive episodes of inordinately loud snoring and excessive daytimesleepiness.

The characteristic snoring pattern noted during sleep apnea is one inwhich inspiratory snores gradually increase when obstruction of theupper airway develops. A loud, choking inspiratory gasp then occurs asthe respiratory efforts succeed in overcoming the occlusion.

The aroused individual subject to sleep apnea is usually aware ofneither the breathing difficulty nor of the accompanying body movementsthat, at times, violently disturb his or her sleep. Typically, adiagnostic study is necessary for an adequate description of theproblematic sleep breathing pattern.

Apneic episodes during sleep are typically defined as cessations of airflow at nose and mouth lasting 10 seconds or more. It can be readilydocumented by so-called poly-somnographic recordings.

There are varying degrees of apnea differentiated by the frequency ofperiodic breathing cessation episodes during sleep, and also the degreeof hypoxia resulting from the related irregular breathing pattern.

When normal breathing is disrupted during sleep, an increased carbondioxide level and a reduced oxygen level appear in the blood. Thesleeping person is then suddenly aroused and gasps for air. This gaspingfor air is often accompanied by a loud snort.

An increased carbon dioxide level in the blood can cause adverse effectson the vital organs. The heart is usually caused to pump harder and at ahigher rate in an effort to compensate for the lack of oxygen. Otherorgans, such as the kidneys and liver are suddenly confronted withincrease blood flow and must adjust to cope with this change. This cyclemay be repeated many times during a night's rest and often results in ageneral lack of proper rest and the restorative benefits thereof.

Some of the health related problems associated with sleep apnea includehypertension, stroke, irregular heartbeat, heart attack as well as thepsychogenic conditions from the loss of restful sleep.

It is generally believed that the cause to this condition is a narrowingof the airways while sleeping. This is believed to be caused by acollapse of the tissue structures surrounding the airway. There seems,however, to be no consensus as to what tissue structures the conditionshould be-attributed to and as to why certain tissue structures close.

There are differing locations and patterns of pharyngeal collapse foreach person. In addition to the physical findings and properties whichcharacterize the pharynx in individuals with obstructive sleep apneasuch as increased collapsibility, increase compliance, increasedresistance and decreased cross-sectional area, the physical propertiesand spatial relationships of the pharyngeal airway, head and neck, aswell as the neuro-muscular integrity of the airway and a mechanism ofbreathing control must also be considered relevant in their contributionto the mechanism and precipitation of upper airway collapse.

In general, it may be considered that obstructive apnea occurs duringsleep when the pharyngeal dilator muscle activity (genioglossus, theinfrahyoid muscle and the palatal muscle group) that normally maintainairway potency during inspiration through dilation of the airways, isdiminished. When the intraluminal negative pressure of the airwayreaches a critical point, the combination of redundant tissues and theloss of pharyngeal muscle tonus cause airway collapse duringinspiration. It should, however, be noted that obstruction has also beenfound to occur during expiration and inspiration.

The prior art is replete with various methods and devices that have beenproposed in attempts to cure snoring and sleep apnea. Treatmentsavailable for sleep apnea vary from weight loss to surgicalinterventions to prosthetic devices. Although weight loss is the mostdesirable approach, few patients are able to comply with their diets andvery few can afford to continue the exposure to the symptoms of sleepapnea for extended periods while losing sufficient weight to reduce orcure the disease.

Surgical approaches are only effective in about 50% of cases. They arealso invasive, expensive and may produce undesirable side effects.

The most successful prosthetic device has been the nasal continuouspositive airway ventilator or pressure known as “CPAP”. The advantagesof the nasal CPAP system are that it produces immediate relief, isnon-invasive and can be used while achieving weight loss, henceeliminating the need for surgery.

The CPAP technique, however, suffers from some important drawbacks. Oneof the primary drawbacks associated with nasal CPAP has been compliance.While nearly all patients are fitted with nasal CPAP as an initialtreatment modality, many cease using the system after a few months. Atleast three primary factors have been identified as the cause for poorcompliance amongst individuals using the CPAP system. One such factor isthe lack of perfect fit and discomfort of wearing a nasal mask. Thepositive pressure of the ventilator flow is often mentioned as anotherfactor. Some patients experience an uncomfortable and annoying sensationof forced air stream in their nose and mouth. Also, dry mouth and throatare often cited as the source of dissatisfaction with the sleep apneaventilators known as CPAP.

Another type of devices used for treating sleep apnea is a valved nasalcannula insertable in the nostril of an intended user. Such cannulaetypically include a body defining a passageway: A valve extends acrossthe passageway and is configured to allow air to flow substantiallyunaffected into the nose of the intended user, but to restrict anyoutgoing flow of air so as to provide a backpressure, with the intentionof keeping the airways open so as to reduce snoring.

Many such devices have a valve taking the form of a flexible leafletextending across the passageway and attached to the body at theperiphery thereof. This is the case, for example, of some of the nasalcannulae described in U.S. Pat. No. 6,626,179 issued Sep. 30, 2003 toPedley, and of some of the cannula described in US Patent Application2006/0150979 of Doshi et al. published Jul. 13, 2006. However, suchleaflets may be influenced by gravity as the orientation of the leafletrelatively to its attachment point will influence its dynamicproperties. Furthermore, these leaflets present a relatively large leverrelatively to their attachment points and therefore have a relativelylarge response time when transitioning between their “free flowing”configurations to their “backpressure providing” configurations.

The above-referenced US Patent Application 2006/0150979 presents somevalved nasal cannulae that alleviate at least in part these problems byhaving valves that are supported at the center thereof by a frameextending across the passageway. Also, some of the valves presented inthis document are supported by the body of the cannula at twodiametrically opposed location and fold in two to let air flow uponinspiration by the intended user. These two types of valves however maylead to the valve leaflet sticking to itself or to the relatively flatsurfaces of the valve support, which again reduces response time and mayeven lead to valve malfunction.

Another problem of these valves resides in that if the valve becomesdetached from the body of the cannula for any reason, the valve may beaspirated by the user of the valve and block the airways of this user.

Accordingly, there exists a need in the industry for an improved valvednasal cannula. An object of the present invention is therefore toprovide an improved valved nasal cannula.

SUMMARY OF THE INVENTION

In a first broad aspect, the invention provides a valved nasal cannula,the valved nasal cannula being insertable in a nose of an intended userand usable to selectively restrict a flow of air flowing through thevalved nasal cannula, the nose having a nostril defining a nostril inletand a nostril vestibule extending inwardly into the nose from thenostril inlet, the valved nasal cannula comprising:

-   -   a cannula body, the cannula body defining a cannula passageway        extending therethrough, the cannula passageway defining a        passageway longitudinal axis, the cannula body also defining a        cannula proximal end and a substantially longitudinally opposed        cannula distal end, the cannula body being, at least in part,        insertable in the nostril with the cannula proximal end        positioned inside the nostril vestibule substantially spaced        apart from the nostril inlet and the cannula distal end        positioned substantially adjacent the nostril inlet;    -   a valve operatively coupled to the cannula body for selectively        restricting the flow of air through the cannula passageway; and    -   a protective grid, the protective grid extending from the        cannula body across said cannula passageway, the protective grid        being located closer to the cannula proximal end than the valve;    -   whereby the protective grid increases the safety of the valved        nasal cannula by preventing relatively large objects from being        inhaled by the intended user while the valved nasal cannula is        inserted in the nostril.

Advantages of the present invention include that the proposed valvednasal cannula is adapted to provide a positive pressure in the airwayusing the breathing of the intended user as a source of positivepressure without the need for an external source of energy and/orcompressed air. The proposed cannula is designed so as to be relativelyeasily insertable and retractable into and from the nasal vestibuleportion of the nose of the intended user without requiring manualdexterity.

The protective grid serves, among other purposes, to prevent the valvefrom obstructing the airways of the intended user should the valvebecome detached from the cannula body.

Also, the proposed cannula is designed so as to be comfortable onceinserted into the nasal vestibule of the intended user. The proposedcannula is designed so as to be substantially fittingly inserted intothe nasal vestibule and, in at least some embodiments, to enlarge thelatter so as to optimize the breathing passageway.

Also, in some embodiments of the invention, the proposed cannula isdesigned so as to be resiliently deformable in order to reduce the riskof injury should the nose of the intended wearer be subjected to animpact while housing the proposed cannula.

The proposed cannula may be used for reducing sleep disorder breathingand/or as a breathing exercise as it may be the case for example inChronic Obstructive Pulmonary Disease (COPD) affecting the inspiratorymuscles. In order to exercise the muscles for such a disease (COPD) thecannula is inserted, for a short period of exercise, upside down intothe nasal nostril or preferably a special cannula having a reverseconfiguration would be used. This configuration allows to induce aresistance to air flow during the inspiration phase rather than at theexpiration phase consequently the inspiratory muscles will gain instrength.

The proposed cannula may optionally be provided with features such asthermal insulation properties in order to reduce the thermal exchangebetween the airway and the air flowing therethrough, filtering and/orair moisturizing means, active substance dispensing means for dispensingactive substances having a stimulating, therapeutic and/or prophylacticeffect.

The proposed device is also designed so as to be manufacturable usingconventional forms of manufacturing and conventional materials such as apolymeric resin injecting moulding process using suitable hypo-allergicresins so as to provide a nasal cannula that will be economicallyfeasible, long-lasting and relatively trouble-free in operation.

The proposed nasal cannula is also designed so as to optimize the airflow therethrough.

The proposed nasal cannula is also designed so as to reduce theresistance to air flow during the inspiratory phase of breathing and soas to be substantially silent during use.

Other objects, advantages and features of the present invention willbecome more apparent upon reading of the following non-restrictivedescription of preferred embodiments thereof, given by way of exampleonly with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the appended drawings:

FIG. 1, in a partial elevational view, illustrates a valved nasalcannula in accordance with an embodiment of the present invention, thenasal cannula being shown inserted into the nasal vestibule region ofthe nose of an intended user, the intended user being shown, in part, inphantom lines;

FIG. 2, in a partial perspective view with sections taken out,illustrates a valved nasal cannula in accordance with an embodiment ofthe present invention;

FIG. 3, in a longitudinal cross-sectional view, illustrates some of thefeatures of a valved nasal cannula in accordance with an embodiment ofthe present invention, the valved nasal cannula being shown with itsvalve in an opened configuration;

FIG. 4, in a partial longitudinal cross-sectional view with sectionstaken out, illustrates part of a valved nasal cannula in accordance withan embodiment of the present invention, the nasal cannula being shownwith its valve in an opened configuration;

FIG. 5, in a partially exploded perspective view, illustrates a valvednasal cannula in accordance with an embodiment of the present invention;

FIG. 6, in a perspective view, illustrates the valved nasal cannulashown in FIG. 5;

FIG. 7, in a top view, illustrates a valved nasal cannula in accordancewith another embodiment of the present invention.

FIG. 8, in a partially exploded perspective view, illustrates a valvednasal cannula in accordance with yet another embodiment of the presentinvention; and

FIG. 9, in a perspective view, illustrates the valved nasal cannulahaving a prehensile protrusion.

DETAILED DESCRIPTION

Referring to FIG. 1, there is shown a valved nasal cannula in accordancewith an embodiment of the present invention generally indicated by thereference numeral 10. The nasal cannula 10 is shown inserted in thenostril 12 of an intended user 14 substantially in register with thenasal vestibule 16 of the intended user 14. The valved nasal cannula 10is insertable in the nose of the intended user 14 and usable toselectively restrict a flow of air flowing through the valved nasalcannula 10. The nostril 12 defines a nostril inlet 15 and a nostrilvestibule, part of the nasal vestibule 16, the nostril vestibuleextending inwardly into the nose from the nostril inlet 15.

As illustrated more specifically in FIG. 2, the nasal cannula 10 has acannula body generally indicated by the reference numeral 18. Thecannula body 18 defines a cannula passageway 20 extending therethroughalong a passageway longitudinal axis 22.

The cannula body 18 also defines a body inner surface 24 and an opposedbody outer surface 26. The cannula body 18 is configured and sized forbeing substantially snugly fitted in the region of the nasal vestibule16. The internal tissue of the nasal vestibule 16 is typicallyconsidered to be less sensitive to tactile stimulation than downstreamnasal tissue and, hence, less susceptible of sending nociceptive signalsto the brain upon a foreign body being inserted therein.

The cannula body 18 typically has a substantially frusto-conicalconfiguration defining a cannula proximal end 28 and a longitudinallyopposed cannula distal end 30. The cannula body 18 is, at least in part,insertable in the nostril 12 with the cannula proximal end 28 positionedinside the nostril vestibule substantially spaced apart from the nostrilinlet 15 and the cannula distal end 30 positioned substantially adjacentthe nostril inlet 15. In other words, the cannula proximal end 28 isadapted to be positioned nearer to the sinuses of the intended wearerwhile the cannula distal end 30 is adapted to be positioned nearer tothe inlet of the nostril 12. Typically, the external diameter of thecannula proximal end 28 is smaller than that of the cannula distal end30. Therefore, in these embodiments, the body outer surface 26 istapered in a direction leading from the cannula distal end 30 towardsthe cannula proximal end 28.

As illustrated more specifically in FIG. 3, the cannula outer surface 26is angled relative to the passageway longitudinal axis 22 by an outersurface-to-longitudinal axis angle 32. Throughout the Figures, the outersurface-to-longitudinal axis angle 32 is shown having a substantiallyconstant value of a few degrees. It should, however, be understood thatthe outer surface-to-longitudinal axis angle 32 could vary withoutdeparting from the scope of the present invention. Typically, thecannula body 18 is configured and sized for providing a radial outwardpressure so as to slightly increase the size of the nasal vestibule 16.

The outer surface-to-longitudinal axis angle 32, as well as the diameterof the cannula body 18 and its length are typically chosen for a givenuser in order to ensure a comfortable yet substantially snug fit in thenasal vestibule 16 of the intended user in order to ensure that thecannula body 18 remains in proper alignment therewith.

The substantially frustro-conical configuration of the body outersurface 26 allows for such a comfortable yet snug fit taking intoconsideration the anatomical configuration of the internal surface ofthe nasal vestibule 16 since it substantially increases the probabilityof having a substantially uniform or constant contact with the internalsurface of the nasal vestibule 16.

In order to reduce the risks of creating a localized pressure onto therelatively sensitive tissues of the nasal cavity, the body outer surface26 is typically provided with a substantially smooth texture. Also, thebody outer surface 26 is typically provided with a substantiallyresiliently deformable characteristic. The cannula body 18 may be madeout of an integral material having such characteristics or,alternatively, the body outer surface 26 may be coated with asubstantially resiliently deformable material.

Typically, the cannula body 18, as a whole, is made out of asubstantially resiliently deformable material and provides resiliency soas to be able to temporarily deform upon an impact of a predeterminedmagnitude being imparted thereon so as to reduce the risk of injury tothe internal tissues of the nose of the intended user 14 should animpact be imparted externally on the nose of the intended user 14. Morespecifically, the cannula body 18 is substantially resilientlydeformable between a body undeformed configuration and a body deformedconfiguration, whereby the cannula body 18 is able to temporarily deformfrom the body undeformed configuration to the body deformedconfiguration upon an impact of the predetermined magnitude beingimparted thereon.

In at least one embodiment of the invention, the cannula body 18 is madeout first of a resiliently deformable material while the body outersurface 26 is coated with a second resiliently deformable material. Thecharacteristics of the first and second resiliently deformable materialsmay be identical or different without departing from the scope of thepresent invention.

In some embodiments of the invention, the cannula body 18 and/or thecoating on the body external surface 26 is made of an hypo-allergicmaterial such as a latex-free polymeric resin so as to reduce the riskof creating an allergic reaction once inserted into the nose of theintended user.

Also, in at least some embodiments of the invention, the cannula body 18and/or the coating on the body external surface 26 is made out of a heatinsulating material so as to reduce the heat transfer between the mucosaof the nose of the intended user and the air flowing through the nasalcannula. The reduced heat transfer may allow for cooler air to reachinternal tissues so as to reduce oedema thereof.

The nasal cannula 10 further includes a valve, or airflow restrictor,for selectively restricting the flow of air through the cannulapassageway 20. The valve is operatively coupled to the cannula body forselectively restricting the flow of air through the cannula passageway.Typically, the valve is a diaphragm-type valve and is positioned in thecannula passageway 20 substantially spaced apart from both the cannulaproximal and distal ends 28 and 30, although other types and positionsof the valve could be used without departing from the scope of thepresent invention.

In the embodiments shown throughout the drawings, and as seen forexample in FIGS. 3 and 4, the valve includes a diaphragm disc 34 madeout of a resiliently deformable material. The diaphragm disc 34 ismounted on a diaphragm frame generally indicated by the referencenumeral 36 for extending across the cannula passageway 20.

As illustrated more specifically in FIG. 5, the diaphragm frame 36includes at least one and preferably an array of supporting ribs orspokes 38 extending across the cannula passageway 20. Typically, thespokes 38 extend substantially radially from a substantially centrallydisposed hub 40 to the body inner surface 24, and therefore extendsubstantially diametrically across the cannula passageway 20.

As illustrated more specifically in FIG. 4, the hub 40 typicallyincludes an anchoring portion for anchoring a central portion of thediaphragm disc 34. The anchoring portion may take any suitable form. Inthe embodiment shown throughout the Figures, the anchoring portionincludes an anchoring stem 42 extending substantially longitudinally inthe cannula passageway 20 from a location substantially at theintersection of the spokes 38. A retaining prong 44 extendssubstantially longitudinally from the anchoring stem 42, the retainingprong 44 having a radius larger than a radius of the anchoring stem 42.Typically, although by no means exclusively, the retaining prong 44 hasa substantially inverted conical configuration defining an annularretaining lip 46. The retaining lip 46 and the adjacent surface of thespokes 38 define a disc-receiving spacing 48 therebetween.

The diaphragm disc 34 is provided with a corresponding a mountingaperture 39 extending therethrough, the mounting aperture 39 having aradius substantially smaller than the radius of the retaining stem 42,and more specifically of the retaining lip 46. The resilient nature ofthe diaphragm disc 34 allows the diaphragm disc 34 to be stretchedradially so as to allow the mounting aperture 39 to be fitted over theretaining prong 44 into the disc-receiving spacing 48. Thisconfiguration of the valve allows to replace the diaphragm disc 34should the diaphragm disc 34 become damaged, or should the needs of theintended user 14 change. For example, the diaphragm disc 34 could beexchanged for a diaphragm disc 34 having a different rigidity, or for adiaphragm disc 34 including a substance able to diffuse into the airflowpassing thereby.

The diaphragm disc 34 is located closer to the body proximal end 28 thanthe diaphragm frame 36. Therefore, the resilient nature of the diaphragmdisc 34 allows the latter to bend when subjected to a pressure impartedthereon. Typically, during the inspiration phase of breathing, the discdeforms substantially freely from a substantially flat closedconfiguration wherein it rests on the spokes 38 to an openedconfiguration shown in FIG. 3 wherein it allows the flow of air throughthe cannula passageway 20, particularly about the periphery thereof.

In some embodiments of the invention, the diaphragm frame 36 and thediaphragm disc 34 have dimensions, configurations and deformationproperties such that a substantially constant backpressure is exerted bythe diaphragm disc 34 upon the intended user expiring air from thecannula proximal end towards 28 the cannula distal end 30 for apredetermined range of expiration flow rate. For example, thesubstantially constant backpressure is from about 0.1 cm H₂O to about100 cm H₂O, and in some embodiments from about 0.5 cm H₂O to about 20 cmH₂O. In some embodiments of the invention, the predetermined range ofexpiration flow rate is from about 0.5 L/min to about 60 L/min, and insome embodiments, from about 10 L/min to about 40 L/min.

Referring back to FIG. 5, there is shown that the proximal end of theribs 38 adapted to contact the diaphragm disc 34 typically have asubstantially pointed configuration defining an abutment apex 50. Theuse of a relatively small contact surface between the spokes 38 and thediaphragm disc 34 is adapted to reduce adherence therebetween and,hence, to reduce resistance or inertia to the initial flow of air duringthe inspiration phase of breathing.

The number of spokes 38, their thickness, the spacing therebetween, andthe thickness and material of the diaphragm disc 34 are typicallycalibrated so as to provide a predetermined resistance to the flow ofair during the expiration phase of breathing. During the expirationphase of breathing, the diaphragm disc 34 is pushed back from its openedconfiguration shown in FIG. 3 to the closed configuration wherein itabuts against the contacting apex 50 of the spokes 38.

Upon the pressure building up in the airway upstream from the nasalcannula 10 as a result of the air being blocked from flowing through thenasal passageway during the initial stage of the expiration phase ofbreathing, the internal pressure will eventually cause the diaphragmdisc 34 to deform into a restricting configuration shown in FIG. 2wherein moveable portions of the diaphragm disc 34 are deflected betweenthe spokes 38 hence creating peripheral passageways 52 through which theair may be expelled out of the nose of the intended user.

Hence, by using a substantially centrally anchored diaphragm disc 34adapted to deform substantially about its periphery, a substantiallyconstant resistance to air flow is provided during both the inspirationand expiration phases of breathing mainly because of the resilientnature of the diaphragm disc 34. The resistance to air flow during theinspiratory phase will be less than the one during the expiratory phaseof breathing. Furthermore, the delay of action of the valve isrelatively short. Also, since the air will flow substantiallyperipherally, the air is distributed along the internal tissues of thenose hence improving the naturally occurring of heat exchange andhumidification of the air flowing there through. Also, the diaphragmdisc deflecting substantially peripherally and abutting againstrelatively small contact surfaces will have a tendency to besubstantially silent and to have a relatively fast response time whenthe intended user switches between inspiration and expiration breathing.

In some embodiments of the invention, as seen in FIGS. 5 and 6, thenasal cannula 10 is provided with a protective grid 54 or other suitableretaining means for ensuring that the diaphragm disc 34 remains withinthe cannula body 18 should the diaphragm disc 34 be unvoluntarilyreleased from its anchoring means. The protective grid extends from thecannula body 18 and extends across the cannula passageway 20. Theprotective grid 54 is located closer to the cannula proximal end 28 thanthe valve, and in some embodiments, is located substantially adjacentthe cannula proximal end 28. The protective grid 54 also increases thesafety of the valved nasal cannula 10 by preventing relatively largeobjects from being inhaled by the intended user while the valved nasalcannula is inserted in the nostril 12.

In addition to, or independently from the valve, the nasal cannula 10may be provided with a filtering medium and/or an air treating medium.For example, the nasal cannula 10 may be provided with an HEPA filterlocated within the cannula body 18 or any other suitable filter. Thenasal cannula 10 may also be provided with a heat and/or humidityexchanger. The nasal cannula 10 may also be provided with a materialmounted therein for dispensing a pharmaceutically active substance, anair treatment substance or any other suitable substance adapted to beactivated by the breathing of the user and/or intrinsically active.

As seen in FIG. 7, the nasal cannula 10′ is not necessarilyfrustro-conical and may present a substantially asymmetric configurationthat better conforms to the shape of the nose of the intended user.

As seen in FIG. 8, a valved nasal cannula 10″ in accordance with analternative embodiment of the invention includes a fixed spoke 38extending substantially diametrically across the cannula passageway 20and a mobile spoke 38″, the mobile spoke 38″ extending substantiallydiametrically across the cannula passageway 20 and being operativelycoupled to the cannula body 18″ and to the fixed spoke 38 so as to berotatable about the passageway longitudinal axis relatively thereto. Inthese embodiments, for example, the cannula body 18″ is substantiallycylindrical. The mobile spoke 38″, by being angled at a variable anglerelatively to the fixed spoke 38, thereby influencing the deformation ofthe diaphragm disc 34 (not shown in FIG. 8) so as to adjust thebackpressure produced by the cannula 10″.

Mounting of the mobile spoke 38″ may be achieved by having a mountingshaft 56 extending substantially longitudinally from the center of thefixed spoke 38. The mobile spoke 38″ is mounted to a substantiallylongitudinally extending sleeve 58 mounted onto the mounting shaft 56.The mobile spoke 38″ defines notches 60 extending substantially radiallyinwardly thereinto. The cannula body 18″ defines substantially radiallyinwardly extending ledges 62 located so as to engage the notches 60. Theledges 62 define recesses 68 for receiving the notches 60 atcircumferentially spaced apart locations, thereby allowing to adjust indiscrete steps the position of the mobile spoke 38″ relatively to thefixed spoke 38.

In some embodiments of the invention, as illustrated in FIG. 9 the nasalcannula 10′″ is provided with a prehensile protrusion 80 of spoke 38′″which provides a grabbing mean for easily removing the nasal cannula10′″ out of the nostril vestibule.

Although the present invention has been described hereinabove by way ofpreferred embodiments thereof, it can be modified, without departingfrom the spirit and nature of the subject invention as defined in theappended claims.

What is claimed is:
 1. A valved nasal cannula, said valved nasal cannulabeing insertable in a nose of an intended user and usable to selectivelyrestrict a flow of air flowing through said valved nasal cannula, saidnose having a nostril defining a nostril inlet and a nostril vestibuleextending inwardly into said nose from said nostril inlet, said valvednasal cannula comprising: a cannula body, said cannula body defining acannula passageway extending therethrough, said cannula passagewaydefining a passageway longitudinal axis, said cannula body also defininga cannula proximal end and a substantially longitudinally opposedcannula distal end, said cannula body being, at least in part,insertable in said nostril with said cannula proximal end positionedinside said nostril vestibule substantially spaced apart from saidnostril inlet and said cannula distal end positioned substantiallyadjacent said nostril inlet; a valve operatively coupled to said cannulabody for allowing said flow of air through said cannula passagewayduring an inspiration phase and selectively restricting said flow of airthrough said cannula passageway during an expiratory phase, wherein saidvalve comprises a diaphragm made out of a substantially resilientlydeformable material and a diaphragm frame extending across said cannulapassageway, wherein said diaphragm frame includes a first spokeextending substantially diametrically across said cannula passageway,and a second spoke extending substantially diametrically across saidcannula passageway, wherein said second spoke is rotatable about saidpassageway longitudinal axis relative to said first spoke such that aspacing between said first spoke and said second spoke is varied, andwherein said diaphragm extends substantially across said cannulapassageway and is deformable into said spacing between said first andsecond spokes; and a protective grid, said protective grid extendingfrom said cannula body across said cannula passageway, said protectivegrid being located closer to said cannula proximal end than an entiretyof said valve; whereby said protective grid increases the safety of saidvalved nasal cannula by preventing relatively large objects from beinginhaled by said intended user while said valved nasal cannula isinserted in said nostril.
 2. A valved nasal cannula as defined in claim1, wherein said diaphragm comprises a disc.
 3. A valved nasal cannula asdefined in claim 2, wherein said diaphragm frame and said diaphragm dischave dimensions, configurations and deformation properties such that asubstantially constant backpressure is exerted by said diaphragm discupon said intended user expiring air from said cannula proximal endtowards said cannula distal end for a predetermined range of expirationflow rate.
 4. A valved nasal cannula as defined in claim 3, wherein saidsubstantially constant backpressure is from about 0.1 cm H₂O to about100 cm H₂O.
 5. A valved nasal cannula as defined in claim 3, whereinsaid substantially constant backpressure is from about 0.5 cm H₂O toabout 20 cm H₂O.
 6. A valved nasal cannula as defined in claim 3,wherein said predetermined range of expiration flow rate is from about0.5 L/min to about 60 L/min.
 7. A valved nasal cannula as defined inclaim 3, wherein said predetermined range of expiration flow rate isfrom about 10 L/min to about 40 L/min.
 8. A valved nasal cannula asdefined in claim 2, wherein said diaphragm frame defines a hub, said hubbeing substantially centrally disposed relatively to said cannulapassageway, said hub defining an anchoring portion, said diaphragm discbeing anchored to said anchoring portion.
 9. A valved nasal cannula asdefined in claim 8, wherein said anchoring portion includes an anchoringstem extending substantially longitudinally in said cannula passagewayfrom said first spoke and a retaining prong extending substantiallylongitudinally from said anchoring stem, said retaining prong having aradius larger than a radius of said anchoring stem; said diaphragm discdefines a mounting aperture extending therethrough, said mountingaperture having a radius substantially smaller than said radius of saidretaining prong; said anchoring stem extends through said mountingaperture.
 10. A valved nasal cannula as defined in claim 2, wherein saiddiaphragm disc is located closer to said cannula proximal end than saiddiaphragm frame.
 11. A valved nasal cannula as defined in claim 2,wherein said first spoke has a substantially pointed configuration in adirection leading towards said cannula proximal end.
 12. A valved nasalcannula as defined in claim 1, wherein said cannula body defines a bodyouter surface, said body outer surface being tapered in a directionleading from said cannula distal end towards said cannula proximal end.13. A valved nasal cannula as defined in claim 12, wherein said bodyouter surface is substantially frustro-conical.
 14. A valved nasalcannula as defined in claim 1, wherein said protective grid is locatedsubstantially adjacent said cannula proximal end.
 15. A valved nasalcannula as defined in claim 1, wherein said cannula body issubstantially resiliently deformable between a body undeformedconfiguration and a body deformed configuration, whereby said cannulabody is able to temporarily deform from said body undeformedconfiguration to said body deformed configuration upon an impact of apredetermined magnitude being imparted thereon.
 16. A valved nasalcannula as defined in claim 1, wherein said valve is positioned in saidcannula passageway substantially spaced apart from both said cannulaproximal and distal ends.
 17. A valved nasal cannula as defined in claim1, wherein said cannula body defines a body outer surface, said bodyouter surface being provided with a substantially smooth texture.
 18. Avalved nasal cannula as defined in claim 1, wherein said cannula bodybeing substantially hypo-allergic.
 19. A valved nasal cannula as definedin claim 1, wherein said cannula body is substantially thermallyinsulating.
 20. A valved nasal cannula as defined in claim 1, furthercomprising a filtering medium or an air treating medium located withinsaid cannula body.
 21. A valved nasal cannula as defined in claim 1wherein said cannula body defines an outer surface, said outer surfacebeing substantially cylindrical.
 22. A nasal cannula insertable in anose of an intended user and usable to restrict a flow of air flowingthrough said nasal cannula, said nose having a nostril defining anostril inlet and a nostril vestibule extending inwardly into said nosefrom said nostril inlet, said nasal cannula comprising: a cannula body,said cannula body defining a cannula passageway extending therethrough,said cannula passageway defining a passageway longitudinal axis, saidcannula body also defining a cannula proximal end and a substantiallylongitudinally opposed cannula distal end, said cannula body being, atleast in part, insertable in said nostril with said cannula proximal endpositioned inside said nostril vestibule substantially spaced apart fromsaid nostril inlet and said cannula distal end positioned substantiallyadjacent said nostril inlet; an airflow restrictor operatively coupledto said cannula body for allowing said flow of air through said cannulapassageway during an inspiration phase and restricting said flow of airthrough said cannula passageway during an expiratory phase, said airflowrestrictor comprising a moveable portion moveable relative to saidcannula body; a frame coupled to said cannula body and comprising afirst rib moveable relative to a second rib, wherein a spacing betweensaid first and second ribs is variable, wherein said moveable portion ofsaid airflow restrictor is deformable into said spacing between saidfirst and second ribs; and a protective grid extending from said cannulabody across said cannula passageway, said protective grid being locatedcloser to said cannula proximal end than an entirety of said moveableportion of said airflow restrictor.
 23. The nasal cannula of claim 22wherein said moveable portion of said airflow restrictor comprises avalve.
 24. The nasal cannula of claim 23 wherein said valve comprises adiaphragm disc.
 25. The nasal cannula of claim 22 wherein said first ribis rotatable relative to said second rib about said passagewaylongitudinal axis.